<template>
  <div class="goods-image">
    <div
      class="large"
      v-show="show"
      :style="[
        { backgroundImage: `url(${images[currIndex]})` },
        {
          backgroundPositionY: bgPositionY + 'px',
          backgroundPositionX: bgPositionX + 'px',
        },
      ]"
    ></div>
    <div class="middle" ref="target">
      <img :src="images[currIndex]" alt="" />
      <div
        class="layer"
        v-show="show"
        :style="{ top: top + 'px', left: left + 'px' }"
      ></div>
    </div>
    <ul class="small">
      <li
        v-for="(img, i) in images"
        :key="img"
        :class="{ active: i === currIndex }"
      >
        <img @mouseenter="currIndex = i" :src="img" alt="" />
      </li>
    </ul>
  </div>
</template>
<script>
import { reactive, ref, watch } from "vue";
import { toRefs, useMouseInElement } from "@vueuse/core";
export default {
  name: "GoodsImage",
  props: {
    images: {
      type: Array,
      default: () => [],
    },
  },
  setup(props) {
    const currIndex = ref(0);
    const usePreviewImg = () => {
      const target = ref(null);
      const show = ref(false);
      // elementX 鼠标基于容器左上角X轴偏移
      // elementY 鼠标基于容器左上角Y轴偏移
      // isOutside 鼠标是否在模板容器外
      const { elementX, elementY, isOutside } = useMouseInElement(target);
      const position = reactive({ top: 0, left: 0 });
      const bgPosition = reactive({ bgPositionX: 0, bgPositionY: 0 });
      watch([elementX, elementY, isOutside], () => {
        show.value = !isOutside.value; // 是否显示大图
        // 控制X轴方向的定位 0-200 之间
        if (elementX.value < 100) {
          position.left = 0;
        } else if (elementX.value > 300) {
          position.left = 200;
        } else {
          position.left = elementX.value - 100;
        }
        // 控制Y轴方向的定位 0-200 之间
        if (elementY.value < 100) {
          position.top = 0;
        } else if (elementY.value > 300) {
          position.top = 200;
        } else {
          position.top = elementY.value - 100;
        }

        bgPosition.bgPositionX = -2 * position.left;
        bgPosition.bgPositionY = -2 * position.top;
      });
      return { target, show, position, bgPosition };
    };
    const { target, show, position, bgPosition } = usePreviewImg();
    return {
      currIndex,
      show,
      target,
      ...toRefs(position),
      ...toRefs(bgPosition),
    };
  },
};
</script>
<style scoped lang="less">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;
  z-index: 500;
  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    background-size: 800px 800px;
    background-color: #f8f8f8;
  }
  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
    position: relative;
    cursor: move;
    .layer {
      width: 200px;
      height: 200px;
      background: rgba(0, 0, 0, 0.2);
      left: 0;
      top: 0;
      position: absolute;
    }
  }
  .small {
    width: 80px;
    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;
      &:hover,
      &.active {
        border: 2px solid @xtxColor;
      }
    }
  }
}
</style>